Back to EveryPatent.com
United States Patent |
5,149,575
|
Soifer
|
September 22, 1992
|
Corner edge bumpers
Abstract
The bumper of the present invention is utilized in conjunction with a
corner edge of a table, piece of furniture, counter or similar article.
The bumper includes a corner edge cover having wall segments overlaid on
the corner sidewalls. The cover wall segments are joined to form an angle
which corresponds to the geometric configuration of the underlying corner
structure. A resilient shield wall includes a substantially
semi-cylindrical wall segment, spaced away from the corner edge cover by
an optimized stand-off distance, and tangentially extending wall segments
bridging opposing sides of the arcuate wall segment with outer regions of
the cover wall segments. The corner edge cover and the shield wall are
integral and are geometrically configured to optimally absorb energy of an
impact through deformation of the shield wall and distribution of the
impact load over the cover wall segments and top plate. A top plate is
integrally connected to the top edges of the corner wall segments to
enhance the energy absorption capabilities of the bumper and provide a
convenient surface for removably mounting the bumper to the corner
structure with double-backed adhesive film.
Inventors:
|
Soifer; Martin T. (7208 Montrico Dr., Boca Raton, FL 33433)
|
Appl. No.:
|
599314 |
Filed:
|
October 17, 1990 |
Current U.S. Class: |
428/188; 52/287.1; 52/717.05; 248/345.1; 428/42.1; 428/192; 428/343 |
Intern'l Class: |
A47B 095/00 |
Field of Search: |
428/40,122,188,343
52/288,716
108/72
248/345.1
|
References Cited
U.S. Patent Documents
1821692 | Sep., 1931 | Copeland | 206/586.
|
2266181 | Dec., 1941 | Epps | 206/586.
|
2376530 | May., 1945 | Dittmann | 206/586.
|
3030728 | Apr., 1962 | Wesman | 206/586.
|
3041775 | Jul., 1962 | Brown et al. | 206/586.
|
3047142 | Jul., 1962 | Heffley | 206/453.
|
3049260 | Aug., 1962 | Stone | 206/586.
|
3072313 | Jan., 1963 | Svendsen | 206/586.
|
3150854 | Sep., 1964 | Jamieson | 248/345.
|
3244347 | Apr., 1966 | Jenk | 206/586.
|
3358725 | Dec., 1967 | Bussard et al. | 150/51.
|
3451709 | Jun., 1969 | Swagger | 248/345.
|
3531040 | Sep., 1970 | Myny | 206/586.
|
3645387 | Feb., 1972 | Hunt | 206/453.
|
3901995 | Aug., 1975 | Conlon | 206/586.
|
3922408 | Nov., 1975 | Smith | 248/345.
|
4012878 | Mar., 1977 | Ellingson | 52/288.
|
4072231 | Feb., 1978 | Helms | 206/453.
|
4106739 | Aug., 1978 | Gasser | 248/345.
|
4120441 | Oct., 1978 | Hurley | 206/586.
|
4202449 | May., 1980 | Bendt | 206/586.
|
4482054 | Nov., 1984 | Gardner | 206/594.
|
4483444 | Nov., 1984 | Gardner | 206/453.
|
4742916 | May., 1988 | Galea | 206/586.
|
4852744 | Aug., 1989 | Van Breemen | 248/345.
|
4877673 | Oct., 1989 | Eckel | 206/586.
|
Other References
ASME publication, Dec. 1969 entitled "The Linearization of the Prebuckling
State and its Effect on the Determined Instability Loads".
A text, The Theory of Elastic Stability, by Timoshenko, published Dec.
1961.
|
Primary Examiner: Thomas; Alexander S.
Attorney, Agent or Firm: Quarles & Brady
Claims
I claim:
1. A bumper for covering an edge formed at the junction of structure
sidewalls comprising:
a corner edge cover for engaging said structure sidewalls and edge, said
cover having cover wall segments connected at adjacent ends to define a
cover junction;
a resilient central arcuate shield wall segment spaced outwardly from said
corner edge cover;
a plurality of resilient shield wall legs, each shield wall leg connecting
tangentially to an opposite side of said arcuate shield wall segment and
extending to connect to one of said cover wall segments, said arcuate
shield wall segment and said shield wall legs integrally connected to form
a shield wall extending away from the cover wall segments in a first
direction; and
a top plate integrally connected to top edges of said cover wall segments
and extending away from and between said cover wall segments in a second
direction, opposite said first direction, whereby said top plate restricts
the separation of said cover wall segments from said structure sidewalls
during impact of an object with said shield wall.
2. The bumper according to claim 1, wherein an arcuate span of said arcuate
shield wall segment is between 150.degree. and 210.degree..
3. The bumper according to claim 1, wherein the shield wall is spaced from
said corner edge cover so that inversion of said shield wall is prevented
during impact with an object.
4. The bumper according to claim 3, wherein a planar distance .delta.
between said cover junction and a center of said arcuate shield wall
segment is approximately equal to
##EQU6##
when K>5.02 and is approximately equal to
##EQU7##
when K.ltoreq.5.02, where
##EQU8##
R=mean radius of said arcuate shield wall segment .theta..sub.o
=half-angle of said arcuate shield wall segment, h=thickness of said
arcuate shield wall segment, .gamma. equals the ratio of a buckling load
for an arch with relaxed boundary conditions to a value of said buckling
load for an arch with fixed boundary conditions, and .lambda. and .eta.
are a solution-pair of the characteristic equation
##EQU9##
5. The bumper according to claim 1, wherein said corner edge cover, said
shield wall and said top plate are made of a material having a durometer
in the range of 75-95 Shore A.
6. The bumper according to claim 5, wherein said material is a low
migration plastic.
7. The bumper according to claim 1, further comprising peelable adhesive
film is applied to a bottom surface of said top plate.
8. The bumper according to claim 1, wherein said top plate is formed to
provide a flexible tab.
9. A bumper for covering the edges of a plate having two corner edges, said
bumper comprising:
a corner edge cover comprising a plurality of cover wall segments
integrally connected to conform to the geometric configuration of the
sidewalls of said plate adjacent said corner edges;
a plurality of shield walls, each shield wall having an arcuate shield wall
segment spaced outwardly from said cover wall segments and a plurality of
shield wall legs extending tangentially from the ends of said arcuate
shield wall segment and integrally connecting to said corner edge cover;
wherein two of said shield wall legs attach to one of said cover wall
segments for overlying a plate surface disposed between said corner edges.
10. The bumper according to claim 9, wherein said corner edge cover and
said plurality of shield walls are elongated.
11. The bumper according to claim 10, wherein said cover wall segments are
formed to provide tabs for accommodating adhesive material.
12. The bumper according to claim 10, wherein an elongated strip of
adhesive material is applied to said elongated corner edge cover.
13. The bumper according to claim 12, wherein the adhesive material is a
double-backed adhesive film having a peelable adhesive side and an
opposite permanent adhesive side.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to bumpers for corner edges such as edges on
tables, counters and other items that have sharp corners and particularly
to removable bumpers for corner edges.
2. Prior Art
U.S. Pat. No. 4,012,878 to Ellingson discloses a wall guard having an
underlying layer conforming to a wall and covering a wall edge and a
second overlying layer spaced from the underlying layer. Both layers
intersect at outboard regions remote from the wall edge. The specific
geometric configuration, thickness, and energy absorption characteristics
of the Ellingson wall guard are not disclosed.
U.S. Pat. No. 4,072,231 to Helms discloses a corner protector having a
pie-shaped top surface and a pair of curved side walls extending
downwardly from the top surface. Curved side walls define an air pocket
between the side walls of the protector and the side walls of the counter
top or table. U.S. Pat. No. 4,483,444 to Gardner discloses a packaging
system. The packaging system includes a corner post that is inserted into
a container. The insert has bulbs or protrusions resting against the
interior sides of the packaging container and has interior walls spaced
from those protrusions to butt the material contained in the container.
U.S. Pat. No. 4,482,054 to Gardner discloses a support and cushioning tube
consisting of a plurality of tubes joined together forming air pockets to
cushion the material contained within the container. U.S. Pat. No.
4,106,739 to Gasser discloses a bumper edge member that defines a
completely enclosed air chamber to cushion impact.
U.S. Pat. No. 3,451,709 to Swagger discloses a side wall and fender
protector. U.S. Pat. No. 3,358,725 to Bussard et al discloses a guard
structure for the rims of canvas baskets. The guard structure is simply
wrapped around the rim of the basket. U.S. Pat. No. 3,244,347 to Jenk
discloses corner post construction that is a collapsed tube inserted into
the corners of a container. U.S. Pat. No. 2,376,530 to Dittmann discloses
solid block corner edge protectors that are inserted into containers to
hold materials stored within the containers. U.S. Pat. No. 1,821,692 to
Copeland discloses a packing case having corrugated corner pieces for
isolating materials stored in the packing case from impact.
U.S. Pat. No. 4,742,916 to Galea discloses corner and edge protectors that
are placed in containers. The protectors are molded fiber that conform to
the corners and edges of items that are placed within containers. U.S.
Pat. No. 4,202,449 to Bendt discloses a protection device for edges of
items that are placed within containers. U.S. Pat. No. 4,120,441 to Hurley
discloses angle edge guards that protect edges of items placed within
containers. U.S. Pat. No. 4,877,673 to Eckel discloses a corner edge
protector for items placed within containers. U.S. Pat. No. 4,852,744 to
Van Breemen and U.S. Pat. No. 3,901,995 to Conlon disclose edge protector
devices that support or protect edges of items placed within containers.
The following references also disclose devices which protect corners and
edges of materials placed in containers: U.S. Pat. No. 3,645,387 to Hunt;
U.S. Pat. No. 3,531,040 to Myny; U.S. Pat. No. 3,072,313 to Svendsen; U.S.
Pat. No. 3,049,260 to Stone; and, U.S. Pat. No. 2,266,181 to Epps.
U.S. Pat. No. 3,030,728 to Wesman discloses cushioning pieces for corners.
The cushioning pieces form a plurality of air bubbles or voids next to the
corner surfaces. U.S. Pat. No. 3,041,775 to Brown et al. discloses a table
corner guide that is a unitary block of material placed on the top surface
of a table. U.S. Pat. No. 3,047,142 to Heffley discloses a mirror corner
protector having bulbs approximate the corner edge of the mirror and along
adjacent side edges.
U.S. Pat. No. 3,150,854 to Jamieson discloses a body guard device for
protecting the corner edges of furniture. The body guard device has a
cylindrically shaped or bulbous protrusion adjacent the corner edge of the
furniture. The Jamieson disclosure does not discuss in detail the
geometric relationship between the cylindrical shield and the balance of
the protector.
An ASME publication was presented during a conference on Nov. 16-20, 1969
entitled "The Linearization of the Pre-buckling State and its Effect on
the Determined Instability Loads" by Kerr and Soifer. This publication
discusses the instability phenomena of elastic solids and provides
nonlinear equations describing the action of those elastic solids under
varying loads. The equations describe the performance of a shallow arch
with fixed boundaries subjected to a uniformly distributed load. A text,
The Theory of Elastic Stability, by Timoshenko, published in 1961,
discloses the buckling of uniformly compressed circular arches and
particularly the critical load for arches with varying angles and boundary
conditions.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a bumper for corner
edges which incorporates an energy absorption design to provide superior
cushioning upon impact.
It is another object of the present invention to provide a bumper wherein
the materials selected also contribute to the energy absorption of the
bumper.
It is a further object of the present invention to provide a bumper which
is elastic and which returns to its original geometric configuration
subsequent to impact.
It is a further object of the present invention to provide a bumper which
can be repeatedly mounted onto a corner edge and removed without damage to
the underlying corner structure.
It is an additional object of the present invention to provide a bumper
which can be easily manufactured at a relatively low cost.
SUMMARY OF THE INVENTION
The bumper of the present invention is utilized in conjunction with a
corner edge of a table, a piece of furniture, counter, or similar article.
The bumper includes a corner edge cover having wall segments overlaid on
the article surfaces adjacent the corner edge. The cover wall segments are
joined together proximate the corner edge and extend therefrom to form an
angle which corresponds to the configuration of the underlying corner. A
resilient shield wall includes a substantially semi-cylindrical wall
segment, spaced away from the corner edge cover, and tangentially
extending wall segments bridging opposing sides of the substantially
semi-cylindrical wall segment with respective outer regions of the cover
wall segments. The corner edge cover and the shield wall are integral and
are geometrically configured to maximize the absorption of impact energy
principally through deformation of the shield wall and to distribute the
impact load over the cover wall segments via the tangential shield wall
segments.
A top plate attaches to the upper edges of the cover wall segments to
permit vertical support of the bumper. The top plate partially absorbs the
impact energy distributed to the corner wall segments, thereby enhancing
the energy absorption capabilities of the bumper. The top plate also
maintains structural integrity by preventing the separation of the corner
wall segments from the underlying corner surfaces during central and
off-center impacts. Further, the top plate provides a convenient surface
for applying reusable adhesives so that the bumper can be attached,
readily removed and subsequently reattached to a furniture corner without
affecting the underlying finish.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects and advantages of the present invention can be found in the
detailed description of the preferred embodiments when reviewed in
conjunction with the accompanying drawings in which:
FIG. 1 illustrates a top view of one embodiment of the corner edge bumper
in accordance with the principles of the present invention;
FIG. 2 illustrates a cross-sectional view of the corner edge bumper from
the perspective of section line A--A in FIG. 1;
FIG. 3 illustrates a perspective view of a dual corner edge bumper used in
conjunction with an extending plate or table edge;
FIG. 4 illustrates a cross-sectional view along section line B--B in FIG.
3, extended to show the bumper as an elongated strip;
FIG. 5 diagrammatically illustrates deformation of an elastic arch; and
FIG. 6 is an exemplary load-displacement curve for the arch shown in FIG.
5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention relates to a bumper for corner edges commonly present
on tables, counter tops, cabinets and other areas that pose a danger of
injury to persons or objects which may impact or hit the exposed corner
edge.
FIG. 1 illustrates a top view of bumper 10, and FIG. 2 illustrates a
cross-sectional view of bumper 10 in the perspective of section line A--A
in FIG. 1. Bumper 10 encases corner edge 12, shown in cross-section in
FIG. 2 and by phantom lines in FIG. 1. Corner edge 12 is formed at the
intersection of corner side walls 14 and 16.
In the preferred embodiment, bumper 10 includes a top plate 18, a corner
edge cover 20 and a shield wall 22. Corner edge cover 20 comprises cover
wall segments 24 and 26 which overlay corner sidewalls 16 and 14,
respectively, when bumper 10 is applied to a corner of article 54. Cover
wall segments 24 and 26 are joined together or formed integrally to
provide a junction 15 corresponding to the corner edge 12 and extend
outwardly. The cover wall segments 24 and 26 can form a variety of angles.
As shown in FIG. 1, the cover wall segments 24 and 26 are in perpendicular
arrangement so that the bumper 10 can be mounted to traditional right
angle corners. However, it is possible to construct the bumper 10 so that
cover wall segments 26 and 28 form acute or obtuse angles to match various
corner configurations.
Shield wall 22 is generally connected to cover wall segments 24 and 26 and
spaced outwardly from junction 15 by a distance 32, also referred to
herein as the standoff distance .delta.. Shield wall 22 is preferably
formed to provide an arcuate shield wall segment 34 and tangentially
extending shield wall legs 36 and 38 which connect to the outer regions 28
and 30 of the corresponding cover wall segments 24 and 26.
In order to optimize the performance of bumper 10 under impact, several
parameters in the design of bumper 10 are coordinated. These parameters
include the arch radius of arcuate wall segment 34, the wall thickness 44
of arcuate wall segment 34, the stand-off distance 32, the durometer of
the material used to form bumper 10 and the contour or geometric shape of
arcuate wall segment 34.
The contour of the arcuate wall segment 34 is preferably a cylindrical
sector with an arcuate span of 150.degree.-210.degree. for a right angle
corner. The use of a cylindrical sector provides a rounded, non-sharp
impact surface. Additionally, this curved surface facilitates the
deflection of off-center impacts. Further, the cylindrical contour of
arcuate wall segment 34 undergoes predictable deformation under impact,
thereby facilitating the design to maximize energy absorption.
The selection of material durometer and wall segment thickness 44 are
governed by the desired impact surface stiffness. Accordingly, when a
cylindrical sector contour is used for arcuate wall segment 34 and the
material durometer and wall thickness 44 are selected, the energy
absorption capabilities of bumper 10 become a function of the stand-off
distance 32 as explained below.
The characteristic behavior of an arcuate impact surface, such as arcuate
wall segment 34, under a centrally applied force is diagrammatically
represented in FIG. 5. The load P represents the resultant of a uniform
impact pressure. The application of load P to the symmetric center of the
arch 70 models the most hazardous impact to bumper 10 because of the
direct alignment of the arch center with the underlying corner 12.
The dashed curve represents the characteristic deformed shape of the
arcuate impact surface under load P. The arch 70 has a wall thickness h, a
half-angle .theta..sub.o, a mean arch radius R and a deformation distance
.delta.. The deformation distance .delta. corresponds generally to the
stand-off distance 32 in bumper 10.
In FIG. 5, arch 70 has relaxed boundary conditions, providing reaction
forces and moments which restrict, but do not prevent, displacement and
rotation of the outer ends of arch 70.
Referring to FIG. 6, the impact performance of arch 70 in FIG. 5 is
represented by a characteristic load-displacement curve. The solid curve
74 illustrates the primary equilibrium path with symmetric arch
deformation. The dashed curve 72 beginning at P.sub.crit bifurcates from
the symmetrical curve at .delta..sub.crit and illustrates a secondary
equilibrium path with unsymmetric arch deformation.
It has been shown in "The Linearization of the Prebuckling State and its
Effect on the Determined Instability Loads" by Kerr and Soifer, ASME Paper
No. 60-WA/APM-1, 1969, that bifurcation in the load-displacement
relationship occurs at .delta..sub.crit when an arch parameter K is
greater than 5.02. Arch parameter K is defined in Equation 1 that follows.
##EQU1##
Where: R=mean radius of arch
.theta..sub.o =half angle
h=wall thickness
Accordingly, when the mean radius, half angle, and wall thickness are
selected so that arch parameter K is less than or equal to 5.02, the arch
deforms only symmetrically, absorbing energy with increasing load and
deformation. For bumpers having arch parameters in that range, the
stand-off distance is preferably no greater than .delta..sub.u depicted in
FIG. 6 since the primary energy absorption level maximizes at impact force
parameter P.sub.u.
However, when arch parameter K is greater than 5.02, the arch deforms
symmetrically absorbing energy with increasing load and deformation until
P.sub.crit is applied and a deformation of .delta..sub.crit is reached. At
that point, the arch dynamically "snaps through" to an inverted form,
thereby releasing the absorbed energy. Consequently, to maximize
absorption of energy in the bumper itself and reduce the likelihood of
inversion, the stand-off distance .delta., for arch parameters K>5.02,
preferably equals .delta..sub.crit.
Referring again to FIG. 6, the load-displacement curve represents the
characteristic performance of an arch under a centrally applied load. The
particular amplitude and width of the curve varies according to the
boundary conditions and arcuate angle of the arch. As the boundary
conditions are relaxed from the fixed conditions prescribed and analyzed
by Kerr and Soifer in the above cited reference, the critical load
P.sub.crit decreases and the corresponding displacement .delta..sub.crit
increases. However, the performance trend represented by the shape of the
characteristic curve remains essentially the same.
To apply the theoretical model to the optimal design of bumper 10, the
following Equations 2 and 3 are used to determine the preferred stand-off
distance 32 between corner 12 and the center of arcuate wall segment 34.
##EQU2##
Where .lambda. and .eta. are a solution pair of the characteristic
Equation 4.
##EQU3##
The modifying factor .gamma. in Equations 2 and 3 is the ratio of the
buckling load with relaxed boundary conditions to its value with fixed
boundary conditions and adjusts the stand-off distance values for the
differences in arcuate angles and boundary conditions from fixed to
relaxed. Table 1 which follows sets forth numerical values for the
buckling loads with relaxed and fixed boundary conditions for different
arch angles. Table 1 is extracted from Table 7-2 in the text, Theory
Elastic Stability, by Timoshenko, 1961.
TABLE 1
______________________________________
Total Fixed Relaxed
Arch Angle Boundaries
Boundaries
______________________________________
30.degree. 294 162
60.degree. 73.3 40.2
90.degree. 32.4 17.4
120.degree. 18.1 10.2
150.degree. 11.5 6.56
180.degree. 8.0 4.61
______________________________________
Accordingly, when the arch parameter K is less than or equal to 5.02, the
arcuate wall segment 34 deforms only symmetrically, following the solid
load-displacement curve 74 in FIG. 6. When K is greater than 5.02, arcuate
wall segment 34 deforms symmetrically until P.sub.crit at .delta..sub.crit
is reached and then unsymmetrically following the dashed line 72 in FIG.
6.
Using the above calculations, the bumper 10 can be preferably designed to
provide a stand-off distance 32 which maximizes the energy absorption
capabilities of bumper 10. For bumpers with an arch parameter K>5.02, the
performance of bumper 10 is optimized by preventing a "snap through"
inversion of arcuate wall segment 34 prior to contact with corner edge 12.
For bumpers designed with an arch parameter K.ltoreq.5.02, performance is
optimized by maintaining increased energy absorption through deformation
of arcuate wall segment 34 until contact with corner edge 12.
To further enhance the energy absorption capabilities of bumper 10, top
plate 18 is preferably connected to the upper edges of cover wall segments
24 and 26. Preferably, top plate 18 is integrally formed with the top
edges of cover wall segments 24 and 26 and constructed of the same
material as cover wall segments 24 and 26 and shield wall 22.
Top plate 18 prevents the separation of cover wall segments 24 and 26 from
the underlying sidewalls 14 and 16. During impact, the impact energy
imparted on shield wall 22 is partially absorbed by the deformation of
shield wall 22 according to the performance characteristics discussed
above. The geometric configuration of arcuate wall segment 34 and shield
wall legs 36 and 38 cause a portion of the energy to be distributed to the
outer regions 28 and 30 of cover wall segments 24 and 26.
Under a load applied to the center of arcuate wall segment 34, the forces
distributed to cover wall segments 24 and 26 urge the inner portions of
corner wall segments 24 and 26 adjacent cover junction 15 away from the
underlying corner walls 14 and 16. This separation outwardly displaces the
connection points of shield wall 22 and corner wall segments 24 and 26,
thereby diminishing the stiffness of shield wall 22.
By preventing the separation of cover wall segments 24 and 26, top plate 18
creates stiffer boundary conditions for shield wall 22. With stiffer
boundary conditions, bumper 10 can absorb greater impact energy for a
given displacement .delta. of shield wall 22. Additionally, top plate 18
partially absorbs the impact energy through tensile strain created in top
plate 18 by the forces distributed to corner wall segments 24 and 26.
Top plate 18 further enhances the performance of bumper 10 during
off-center impact. Application of impact loads on shield wall legs 36 and
38 urges the outer portions 28 and 30 of corner wall segments 24 and 26 to
separate from corner sidewalls 14 and 16. This separation of outer
portions 28 and 30 is prevented by top plate 18, thereby reducing the
displacement of shield wall 22 for a given impact load.
In addition to improving the energy absorption capabilities of bumper 10
under both central and side impacts, top plate 18 permits vertical support
of the bumper structure when applied to the corner of article 54. Top
plate 18 is disposed on the top surface of article 54 and provides a
convenient surface for applying adhesive material to secure bumper 10 to
article 54.
Preferably, the underside of top plate 18 accommodates a double-backed
adhesive film 56. The adhesive film preferably provides permanent adhesive
to securely attach to top plate 18 and peelable adhesive for temporary
attachment to the top surface of the article corner. Alternatively, any
adhesive material which permits repeated attachment and removal of bumper
10 to article 54 without damage to the article finish can be used.
Top plate 18 can alternatively be constructed to provide a tab (not shown)
for accommodating adhesive film 56. This optional tab can be formed to
provide a flexible central portion of top plate 18 to facilitate
application and removal of bumper 10.
Referring to FIG. 3, the corner edge bumper can be adapted for application
to blunt corners, such as table ends, which comprise two edges. In this
embodiment, a dual edge bumper 100 generally includes two corner edge
bumper portions 110 and 112 covering two corner edges 114 and 116. Corner
edges 114 and 116 can be part of an extending plate 120, such as a table
top or an extending counter top lip having upper and lower sharp corner
edges. Bumper portions 110 and 112 include respective corner edge covers
122 and 124, arcuate shield wall segments 126 and 128 and associated
tangential shield wall legs 130, 132, 142 and 144. Adjacent shield wall
legs 130 and 132 extend from arcuate wall segments 126 and 128 and connect
to adjoining cover wall segments 138 and 140. Outer shield wall legs 142
and 144 extend tangentially from arcuate shield wall segments 126 and 128
to connect to the corner edge covers 122 and 124.
Cover wall segments 138 and 140 are preferably integrally connected.
Adjacent tangential wall segments 130 and 132 can be further separated for
thick plates to maintain the optimized impact absorption characteristics
of the each bumper with respect to the its particular corner edge.
The outer portions of corner edge covers 122 and 125 can be extended, as
shown by extension 154, to provide greater adhesion surface area and
optional tab 212, shown in FIG. 4.
FIG. 4 illustrates a cutaway view along section line B--B in FIG. 3. The
dual edge bumper 100 is extended to illustrate an elongated configuration
for covering a substantial length of a table edge. Outer region 152
includes the option of a tab 212 carrying adhesive 214. The adhesive 214
is placed on the inboard side of the optional tab 212, which facilitates
the removal of bumper 100 from the underlying article. Shield wall 128 is
preferably spaced apart from corner edge cover 124 as described earlier.
The intersection between the shield wall and the outer region of the cover
wall segment is shown as dashed line 220.
The bumper 10 is preferably an integral item and is made of an elastic
material that upon impact, deforms and then returns to its original
geometric shape. Preferably, a low migration plastic having a durometer (a
measure of elasticity) in a range from 75 to 95 Shore A. Most preferably,
a low migration PVC having 85 Shore A durometer is utilized as the
material.
With the selection of a material durometer in the preferred range, an
example of one preferred bumper design can be determined as follows:
##EQU4##
from Table 1,
##EQU5##
from Eq. 1, K=9.85; from Eq. 2, since K>5.02, .delta.=.delta..sub.crit
=0.231".
Having described and illustrated the preferred embodiments of the present
invention, it is intended that the scope of the invention not be limited
by such description and illustration but only by a reasonable
interpretation of the appended claims. The claims appended hereto are
meant to cover modification and changes within the scope and spirit of the
present invention.
Top